diff options
authorJosh Poimboeuf <jpoimboe@redhat.com>2017-09-15 02:17:11 -0500
committerIngo Molnar <mingo@kernel.org>2017-09-15 11:31:57 +0200
commit97dab2ae7e8473a821f72a039ead0f36b12ba22d (patch)
parentdf968c9329f6e5cf3596a0a54adb6f749747a746 (diff)
objtool: Fix object file corruption
Arnd Bergmann reported that a randconfig build was failing with the following link error: built-in.o: member arch/x86/kernel/time.o in archive is not an object It turns out the link failed because the time.o file had been corrupted by objtool: nm: arch/x86/kernel/time.o: File format not recognized In certain rare cases, when a .o file's ORC table is very small, the .data section size doesn't change because it's page aligned. Because all the existing sections haven't changed size, libelf doesn't detect any section header changes, and so it doesn't update the section header table properly. Instead it writes junk in the section header entries for the new ORC sections. Make sure libelf properly updates the section header table by setting the ELF_F_DIRTY flag in the top level elf struct. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 627fce14809b ("objtool: Add ORC unwind table generation") Link: http://lkml.kernel.org/r/e650fd0f2d8a209d1409a9785deb101fdaed55fb.1505459813.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 files changed, 6 insertions, 1 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index b4cd8bc62521..24460155c82c 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -563,6 +563,7 @@ int elf_write(struct elf *elf)
struct section *sec;
Elf_Scn *s;
+ /* Update section headers for changed sections: */
list_for_each_entry(sec, &elf->sections, list) {
if (sec->changed) {
s = elf_getscn(elf->elf, sec->idx);
@@ -570,13 +571,17 @@ int elf_write(struct elf *elf)
return -1;
- if (!gelf_update_shdr (s, &sec->sh)) {
+ if (!gelf_update_shdr(s, &sec->sh)) {
return -1;
+ /* Make sure the new section header entries get updated properly. */
+ elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
+ /* Write all changes to the file. */
if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
return -1;